The study report on Vanadium dioxide thin films of about 100nm thickness deposited using pulsed laser deposition on Si (100). The novel phase change reported is attributed to the post-treatment of the films via ion implantation with 25 KeV C+ ion beam at varying particle fluence (1E15, 1E16, and 1E17 /cm2). At the initial fluence, the preferred phase is retained while amorphization and recrystallization of the film is observed as the fluence increase to 1E16 ions/cm2and 1E17 ions/cm2, respectively. The phase transition of the samples is observed to occur at a temperature below 320 K while stabilization of the low phase structure is observed for the middle fluence. Further increase restores the SMT behaviour/trend that occurred at elevated temperatures.

A new deep level transient spectroscopy (DLTS) technique is described, called half-width at variable intensity analysis. This method utilizes the width and normalized intensity of a DLTS signal to determine the activation energy and capture cross section of the trap that generated the signal via a variable, kO. This constant relates the carrier emission rates giving rise to the differential capacitance signal associated with a given trap at two different temperatures: the temperature at which the maximum differential capacitance is detected, and an arbitrary temperature at which some nonzero differential capacitance signal is detected. The extracted activation energy of the detected trap center is used along with the position of the peak maximum to extract the capture cross section of the trap center.

As advanced CMOS scaling with FinFETs continues beyond the 10/7nm nodes, contact resistance (Rc) remains a dominant component affecting device performance. The FinFET Source/Drain (S/D) contact area has become smaller with fin pitch scaling, resulting in drastically increased Rc. To achieve higher drive currents and fully realize the performance gain from FinFET architectural changes, it is critical to continue to reduce contact resistivity (ρc) < 1.0x10-9 Ω.cm2 for both NMOS and PMOS. In this paper, we review the recent trends for ρc reduction for advanced CMOS devices and discuss approaches that have demonstrated reduction in ρc, such as in-situ heavily doped epitaxial films for S/D, advanced ion implantation and laser anneals. The implant techniques include pre-amorphization implants (PAI), dopant boosting implants, cryogenic (-100°C) implants for damage engineering and plasma doping (PLAD) for conformal doping of high aspect ratio (HAR) contacts. With such high levels of doping from epi and implants, advanced laser anneals are key for epitaxial regrowth and formation of metastable alloys for dopant supersaturation or segregation in top layers. Millisecond laser anneal (MSA) improves dopant activation and nanosecond laser anneal (NLA) permits superactivation, and both have become key enablers for ρc reduction. This paper also reviews two alternative contact approaches: dual silicide scheme and wrap-around contact (WAC), as potential pathways to further reduce Rc for advanced CMOS nodes.

The emergence of 2D materials has led to increased attention on correlating the structural, optical, and optoelectronic properties of atomically thin transition metal chalcogenides like MoS2. We demonstrate the tunability of the photoluminescence (PL) properties of bulk MoS2 via implantation of Nb ions. Raman spectroscopy is used to confirm the p-type doping. The PL intensity of MoS2 is drastically enhanced by the adsorption of p-type dopants. X-ray photoelectron spectroscopy (XPS) is used to study the change of MoS2 structure post-implantation. Our results provide a new route for modulating the optical properties of two-dimensional semiconductors. The strong and stable PL from defect sites of MoS2 created by Nb ion implantation may have promising applications in optoelectronic devices.

Research focus in recent years on magnetic behaviour of transition metal (TM) ions embedded in semiconductors has shifted from intrinsic effects to extrinsic effects such as the formation of nanoclusters of the TM ions and the influence of the host matrix on their magnetic behaviour. Our studies, using conversion electron Mössbauer Spectroscopy and magnetization measurements, on SiO2 and Al2O3 substrates implanted with 4 at. % Fe, show ferromagnetic behaviour of α-Fe clusters in amorphous SiO2, but α-Fe2O3 clusters displaying superparamagnetic relaxation in crystalline Al2O3.

200 μm thick solution annealed AISI 316L stainless steel foils were implanted with Ar ions to produce a 0.25 at. % concentration-depth plateau extending from the near surface to a depth of ≈ 250 nm, and then annealed at 550°C for 2 hours to form small Ar bubbles and Ar-vacancy clusters. Distinct sets of samples (including control ones without Ar) were irradiated at the temperature of 550 °C with Au ions accelerated at 5 MeV to produce an average damage content about ≈36 dpa at the region containing the Ar plateau. These samples were investigated by transmission electron microscopy using plan-view specimens prepared by ion milling. In contrast with the control samples where the irradiation causes the formation of a high concentration of extended defects and large cavities, carbonite precipitation of 1:1 metal-carbon (MC) content with a cubic structure occurs only in the samples containing the Ar bubbles. This precipitation phenomenon is not commonly observed in the literature. The results are interpreted considering that the precipitate growth process requires the emission of vacancies which are synergistically absorbed by the growth of the Ar bubbles.

As an extension of our previous proving that ion beam synthesis is an efficient route to form doped silicon nanocrystals (nc’s) [1, 2], we show here that ion beam synthesis, by co-implantion of the dopant and of the constituents of the alloy, followed by a single high temperature anneal, is also a convenient way to grow more complex structures, such as As doped nc’s of Si1-xGex alloys.

Rutherford backscattering spectrometry (RBS) is used to measure the impurity profiles and evaluate the average concentration of the various species (Si, Ge, As). The formation of the nc’s is evidenced by TEM observation and further confirmed by Raman and XRD analysis, which also allow us to estimate the Ge content of the nc’s.

The incorporation of As inside the Si1-xGex nc’s is attested by the presence of the characteristic Ge-As related line in the Raman spectra of the As-doped samples, and strengthened by the increased conductivity of MOS structure including such doped nc’s inside the dielectric film.

The electrical characteristics of Au/Ni/Ti/ n-SiC contacts have been examined as a function of implant dose (1013-1014 ions/cm2) at 5 KeV and temperature of annealing (750-1000 °C). Measurements of specific contact resistance, ρc, were approximately constant at lower implant doses until increasing at 1 x 1015 ions/cm2 for both C and P ions. Annealing at a temperature of 1000 °C has reduced the value of ρc by an order of magnitude to ∼1 x 10-6 Ω.cm2 at implant doses of 1013-1014 ions/cm2. Auger Electron Spectroscopy (AES) has shown that annealing at 1000 °C resulted in a strong indiffusion of the metallization layers at the interface.

We report on the formation of shallow junctions with high activation in both n+/p and p+/n Ge junctions using ion implantation and Flash Lamp Annealing (FLA). The shallowest junction depths (Xj) formed for the n+/p and p+/n junctions were 7.6 nm and 6.1 nm with sheet resistances (Rs) of 860 ohms/sq. and 704 ohms/sq., respectively. By reducing knocked-on oxygen during ion implantation in the n+/p junctions, Rs was decreased by between 5% and 15%. The lowest Rs observed was 235 ohms/sq. with a junction depth of 21.5 nm. Hall measurements clearly revealed that knocked-on oxygen degraded phosphorus activation (carrier concentration). In the p+/n Ge junctions, we show that ion implantation damage induced high boron activation. Using this technique, Rs can be reduced from 475 ohms/sq. to 349 ohms/sq. These results indicate that the potential for forming ultra-shallow n+/p and p+/n junctions in the nanometer range in Ge devices using FLA is very high, leading to realistic monolithically-integrated Ge CMOS devices that can take us beyond Si technology.

Ternary Fe-Co-Si B20 phase structure was formed by implanting Fe and Co ions consecutively into Si(100) substrate at 50 keV energy, each with a fluence of 1.0 × 1017 atoms/cm2 and post-thermal vacuum annealing at 500 oC for 60 minutes. An in-situ magnetic field was used to enhance the formation of the ternary phase in the Si substrate during the implantation process. The magnetic field of 0.05 T was applied perpendicular to the incoming ion beam direction and parallel to the substrate surface to form elongated clusters in the transverse direction of the sample. Prior to the implantation of ions, the implant ions depth profiles were simulated using a dynamic ion-solid interaction code (TRIDYN). The TRIDYN simulation predicted a saturation in the peak concentration of the Fe and Co ions at a fluence of 1.0 × 1017 atoms/cm2. XPS measurement at the peak concentration depth (40 nm) showed the presence of Fe (23 %) and Co (32 %) in the Si matrix. XRD characterization confirmed the presence of stable Fe-Co-Si B20 phase structure in the annealed samples implanted with the in-situ magnetic field.

Titania nanotube arrays were synthesized electrochemically by anodization of titanium foils, and the synthesized titania nanotubes were then implanted with indium ions. The effect of In-ions implantation on crystallization and phase transformation of titania was investigated using in-situ high-temperature X-ray diffraction and synchrotron radiation diffraction from room temperature to 1000 °C. Diffraction results show that crystalline anatase first appeared at 400 °C in both the non-implanted and the In-implanted materials. The temperature at which crystalline rutile temperature appeared was 600 °C for non-implanted materials and 700 °C for In-implanted materials, and the indium implantation inhibited the anatase-to-rutile transformation. Although In3+ is expected to increase oxygen vacancy concentration and then the rate of titania transformation, the observations are consistent with implanted In-ions occupying the Ti sublattice substitutionally and then inhibiting the transformation. The relatively difficult anatase-to-rutile transformation in the In-implanted material appears to result from the relatively large In3+ radius (0.080 nm). The In3+ partly replaces the Ti4+ (0.061 nm), which provides a greater structural rigidity and prevents relaxation in the Ti bonding environment.

In this paper the defects generated by ion implantation in 4H-SiC DIMOSFET (Double Implanted MOSFETs), and their evolution after annealing process, have been studied in detail. The point defects generated by the source or body implantation process have been detected by micro-photoluminescence (µPL) and the effect of these defects on the electrical characteristics of the DIMOSFET has been studied. The role of the annealing process has been carefully investigated by using different temperatures. It appears fundamental for the restoring of the crystal damage. The effect of the ion implantation dose has been investigated as well. By reducing the source ion implanted dose a large decrease of point defects has been detected and a considerable improvement of the electrical characteristic of the DIMOSFET has been observed.

The formation and stability of radiation-induced defects in structural materials in reactor environments significantly effects their integrity and performance. Hydrogen, which may be present in significant quantities in future reactors, may play an important role in defect evolution. To characterize the effect of hydrogen on cascade damage evolution, in-situ TEM self-ion irradiation and deuterium implantation was performed, both sequentially and concurrently, on nickel. This paper presents preliminary results characterizing dislocation loop formation and evolution during room temperature deuterium implantation and self-ion irradiation and the consequence of the sequence of irradiation. Hydrogen isotope implantation at room temperature appears to have little or no effect on the final dislocation loop structures that result from self-ion irradiation, regardless of the sequence of irradiation. Tilting experiments emphasize the importance of precise two-beam conditions for characterizing defect size and structure.

We investigate the structural evolution of Er/Si nanoclusters obtained in co-implanted fused silica upon annealing via Raman spectroscopy and transmission electron microscopy. The effect of annealing temperature (900–1200 °C) on the nature and the relative fraction of the formed amorphous-Si, Si nanocrystals (Si-nc), and amorphous Er nanoparticles (Er-np) was determined in this ternary Er–Si–O system, showing a change of growth regime above 1100 °C due to the formation of mixed Er/O/Si aggregates. We observe that the nucleation and growth of amorphous Er-np and Si-nc are mutually affected. The 2-fold increase in the size of Er-np when no excess Si+ is present in the matrix indicates that the formation of Si-nc in the proximity of Er clusters hinders Er diffusivity above 1100 °C. This finding shows the importance of nanoclustering for improving the thermal stability of Er-doped silica systems.

The effect of low energy implantation of P or C ions in 3C-SiC on the properties of Ti/Ni/Au contacts has been examined for doses in the range 1013-1015 ions/cm2. Measurements of specific contact resistance, ρc, were performed using the two-contact circular test structure. The magnitude of ρc for the Ti/Ni/Au contacts on unimplanted SiC was 1.29 x 10−6 Ω.cm2. The value of ρc increased significantly at an implant dose of 1 x 1015 ions/cm2. The dependence of ρc on ion dose has been measured using both C and P implant species.

The importance of ZnxMg1-xO is increasing day by day because of its wider bandgap than ZnO. This ternary semiconductor finds its application in the fields of optoelectronics, spintronics, superlattices due to its unique blueshifted UV-luminescent property. n- to p-type conduction which is the motive of the project can be achieved with increasing Mg content in ZnMgO. The optical characteristics of the nitrogen doped ZnxMg1-xO (x=0.85) grown on 2 inch Si <100>wafer by RF sputtering are studied and analyzed thoroughly using low temperature (15K) photoluminescence measurements. Nitrogen implantation was carried out by Plasma immersion Ion Implantation technique on the sample. Rapid Thermal Process was employed to remove defects resulting from implantation. The samples were annealed at 700°C, 800°C, 900°C, and 1000o C for 10 seconds in an oxygen ambient. Photoluminescence (PL) measurements were performed at low temperature (15K) which exhibited acceptor-bound-exciton peak (A°X) and donor-bound-acceptor pair (DAP) at 3.336 eV and 3.236 eV respectively. At 3.364 eV, S peak was found for the sample annealed at 800°C after implantation. This peak was attributed to the existence of ZnO-like composition. Localized and de-localized exciton peaks were found around 3.42 and 3.45 eV respectively. This result is very important because though dominant acceptor peak was not found but proper optimization of the parameters can lead to p-type ZnMgO which is the main motive of this project.

This work shows that realistic irradiation-induced phase separation and the resulting microstructures can be obtained via an adapted Phase Field (PF) modelling combined with atomistic Monte Carlo simulations in the pseudo-grand canonical ensemble. The last allow for calculating the equilibrium phase diagram of the silver-copper alloy, chosen as a model of binary systems with large miscibility gap and, for extracting the parameters of the excess free-energy PF functional. Relying on this methodology, the equilibrium phase diagram of the alloy is predicted in excellent agreement with its experimental counterpart whereas, under irradiation, the predicted microstructures are functions of the irradiation parameters. Different irradiation conditions trigger the formation of various microstructures consistently presented as a non-equilibrium “phase diagram” aiming at facilitating the comparison with experimental observations.

Under controlled irradiation of low energy carbon ions, photoluminescence (PL) study of InAs quantum dots prepared with different capping structures (GaAs and InAlGaAs) was carried out. Samples were investigated by varying implantation energy from 15 keV to 50 keV with fluence ranging between 3 × 1011ions/cm2 and 8 × 1011 ions/cm2. For fixed fluence of 4 × 1011ions/cm2, low temperature PL showed enhancement in a certain range of energy, along with a blue shift in the PL peak wavelength. In contrast, with varying fluence at fixed implantation energy of 50 keV, PL enhancement was not significant, rather a drop in PL intensity was noted at higher fluence from 5 × 1011 to 8 × 1011 ions/cm2. Moreover, carbon ion implantation caused a blue shift in the PL emission peak for both energy and fluence variations. PL intensity suppression was possibly caused by the formation of non-radiative recombination centers (NRCs) near the capping layer, while the corresponding blue shift might be attributed to stress generation in the capping layer due to implantation. As-grown and implanted InAlGaAs capped samples did not exhibit much variation in full width at half maxima of PL spectra; however, significant variation was observed for the GaAs capped sample. These results validate that InAlGaAs-capped QDs are more immune to ion implantation.

Over the last few years, significant improvements in sources, columns, detectors, control software, and accessories have enabled a wealth of new focused ion beam applications. In addition, modeling has provided many insights into ion-sample interactions and the resultant effects on the sample. With the knowledge gained, the community has found new ion-beam induced chemistries and ion-beam sources, allowing extending nanostructure fabrication and material deposition to smaller dimensions and better control for direct write and patterning. Insignificant proximity effects in resist-based ion beam lithography, combined with the availability of sub-nm ion spot sizes, opens the way to sub-10 nm structures and dense patterns. Additionally, direct-write ion beam nanomachining can process multilevel structures with arbitrary depths in one single process step, with all the information included in a single standard design file, thus enabling fabrication applications not achievable with any other technique.

4H-SiC substrates were annealed at 1500 °C for 30 min in 0.01 MPa Ar gas flow to make a graphene film. To clarify the effect of Al ion implantation and pre-plasma treatment, the graphene was fabricated on four different kinds of SiC substrates: without plasma treatment, with plasma treatment, Al ion-implanted without plasma treatment and Al ion-implanted with plasma treatment. The graphene films were analyzed by AFM and Raman spectroscopy. The Al ion implanted sample, which was then processed by CF4 plasma, showed small surface roughness of 3.49 nm (RMS), while the sample without CF4 plasma treatment showed large surface roughness of 8.41nm. Similar results were also observed for SiC samples without Al ion implantation. In Raman spectra, strong D-band, G-band and 2D-band signals were detected on both ion-implanted samples after annealing at 1500 °C, but weak D-band were observed on both samples without Al ion implantation. Raman mapping (2D-FWHM) showed that the graphene on ion-implanted SiC treated with CF4 plasma was more homogeneous than the one without CF4 plasma treatment. Hall measurements for SiC without Al ion implantation showed that graphene on SiC treated with CF4 plasma has higher mobility (389 cm2/Vs) than that without plasma treatment (136 cm2/Vs). Additionally, p-type graphene can be fabricated on Al ion-implanted SiC by CF4 plasma treatment.